Heater-circuit control



March 1931. w. H. HARRINGTON 1,795,122

HEATER CIRCUIT CONTROL Filed Nov. 25. 1929 2 Sheets-Sheet 1 1 INVENTQR WILLIAM H. HARRINGTON March 3, 1931. w. H. HARRINGTON 1,795,122

HEATER CIRCUIT CONTROL Filed Nov. 23, 1929 2 Sheets-Sheet 2 LOWER BLADE UPPER BLADE I I F A c B HIGH M-N IN SERIES ACROSS A-B MED N ALONE B-C Low M-N 1N SERIES B-c Ff LOWER BLADE UPPER BLADE Q I AcB szQ 4 HIGH M-N PARALLEL ACROSS B-C MED M ALONE B-C LOW M-N IN SERIES W 5-6 Fig. 5. 86 ad, 1 l 26 3] 22 44 41 42 20 i I I/ i y: 21 98 4r Y 5} j 94 I 7- /'r a 9 l 2 25/ /j v 7 4 3 WILLIAM H.HARRINGTON 9 9 1 :7 &z1; ai-zarne ya Patented Mar. 3, 19ml aha w Application heroin e a Q. lf'it ii third ll. h s aill lay; "J

This invention haste do the control of electric circuits in which there are heating elements arranged to he connected electrically in diilerent ways to give diflerent degrees of heat. t provides a switch base which may be used with two di sets of related contacts and switch hlades to enable three degrees of heat to he obta ned either orn a three wire supply having neutral w.

rom a two wire supply. 'T as connectio' the heating elements are the same regal of which set of lined contacts and s lolades is used. This switch lease also niinals in form of a receptacle for tachinent plug to which leadin the heating elements a e connected.

A preferred rorrn or invention is described and is illustrated in the accoinpanying drawings to which reference is made inthe course of the description.

Figure l is atop View of a switc oase having the switch mechanism in place a well therein but having the thumb piece or actuator broken away.

Figure 2 is a View of the bottom of the same base.

Figure 3 is side View, partly in section, of this base with the attachment plug, to which the wires leading to the heating elements are connected, in place thereon.

Figure 4: is a side View of recent plug.

Figure 5 is a diagrammatic View of one set of related fixed contacts and switch blades showing the connections of the former to an Edison three wire circuit and to a two-element heater, and showing the blades in their open-circuit or 0d position.

Figure 6 is a similar view showing a set of contacts and switch blades for connecting the same heater to a two wire supply, shown here the said attach as being two wires of an Edison three-wire circuit.

The base is formed as a block 10 of molded insulating material and has a circular switch well ill on one side toward one end and a receotacle the opposite side at the ther n this opposite side, which l he. called e hot re three t nsverse grooves 12% b .ch adapted to receive a bus har tch mechanism is niounted in the well 1i. mechanism is not here in de. l r ay he of any stable construction rn the switch blades in unison ion through steps of 90 each, 'oositions. There are es,i he terms shown here. line s indle of switch mechanism is supported by a yolre 5 extending across the swit h well and made a hole at its mid point so it may slip over the spindle, all according to conventional practice. A novel feature however is the extension of the wings or lateral arms 16 at the ends of the yoke so that the holes 17, through which the screws 18 extend to hold the yoke to the lease, are 90 apart and are equally spaced. By reason of this the yoke may he placed on the loase in such a way that it extends along the long axis of the lease, as in Figure 1, or right angles thereto. Since the yoke serves to mount the switch base on a range or other place of use, the holes 19 at the ends of the yoke being for this purpose, the base may he mounted in either of two positions at right angles to each other.

The fixed contacts are mounted in hays opening to the switch well and thus they are supported on the base and extend into the well. The hays are 90 apart around the well to correspond to the four points with which the switch blade arms register when at rest. These points about the well at which the bays are located will be termed quarter points or generically, switch points since they are ed wire or the supply circuit. A

till

the points at which the fixed contacts may be put to engage arms of the switch blades. At either side of the long axis of the base are the bays 20, 21, (Figs. 1 and 7) which'provide ledges at the level of the upper switch blade, while midway around the well between these two bays are the bays 22, 23, each of which has a ledge 24 at the level of the lower switch blade and two ledges 25 on. opposite, sides thereof at the level of the upper blade.

The contacts used in bays 22, 23 are of two types. One type has wings 26 which extend to the ledges 25 and thus enable the contact portion to extend into the well at the upper blade level. The other typeis like those used in the other bays 20, 21, having simply a shank that rests on the ledge 24 ror support. W hen it is desired to have a low contact at either of the bays 20, 21 where the ledges are at the upper blade level, a contact is used that has its blade engaging portion oilset downwardly from the shank which rests on the ledge. Bearing this in mind, the two sets of contacts and blades now will be described,

' the references to the drawingsbeing chiefly to Figures 5 and 6.

When a three wire supply circuit is used and connections are made to all three wires, there is a short contact 81 on the ledge 24 of the bay 22 and a long contact 32 on the corresponding ledge of the bay 23 for co-action with a lower blade having three long arms 33, 3d, 35 and a short arm 36. To is understood that a long blade arm will engage either a long or a short fixed contact and that a short blade arm will engage only a long contact. liour upper fixed contacts are used, a short one 41 on the ledges 25 of the bay 22, a short one 42 in the bay 21, a long one 43 on the ledges 25 or" the bay 23 and a long one at on the ledge in the bay 20. The upper blade which co-operates with these has two short arms 45, l6 spaced 180 and a long arm 4'? midway between them.

()ne outside wire A is connected with the upper short contact ll and the other outside wire B with the lower short contact 31. The neutral wire C is connected with the upper long contact 43. The heating elements M and N are connected with the load terminals and the latter are connected with the remaining tired contacts, as shown, the upper short contact 42 being connected with the terminal which is connected with the mid-point of the elements M, N. The lower long contact 32 is connected with the terminal 51, and the upper long contact at with the terminal 52, these terminals being connected in turn with the outside ends of the heating elements N and M respectively.

The three degrees of heating are obtained by turning the switch blades 30 and 40 in unison from the position shown to the three other possible positions. When thus turned clockwise 90, the heating elements M, N

igrearaa are put in series across the outside wires A, B giving a high degree of heating. 'Another 90 turn puts the element N alone across the outside wire B and the neutral wire C to give a medium degree of heating. The low heat is obtained by another quarter turn by which the two heating elements are connected in series across the neutral wire C and the outside wire B. ll make no claim to these circuit connections as they form the subject of the Nero application Serial No. 850,055, filed March 26, 1929.

Vfhen but two supply wires are used, whether two of the wires of a three wire system or the two of a two wire system, the arrangement shown in Figure 6 is preferred.

The lcwerblade has associated with it a long contact 61 on the ledge 24 of the bay 22, a short one 62 on the corresponding ledge of thebay 23 and a long contact 63 in the bay 20, the blade itself having two opposite long arms 64, 65 and a single short arm 66. There are two long upper contacts, one 71 in the bay 21, and another 72 on the ledges 25 of the bay 23. A third upper contact 73 is short and isin the bay 20. The upper blade has a long arm 74 and two opposite short arms 7 5, 7 6. 1

The lower blade 61 and the upper blade '7 2 are connected respectively with the outside wire B and the neutral wire C, but may of course be connected to any other two wires of diilerent potential. The heating elements M, N are connected with the terminals 50, 51. 52 in e-Xactlythe same way as that shown in Figure 5 and the terminals are connected with the same quarter points on the base, the terminal 50' being connected with the long upper contact 71, the terminal 51 with the lower short contact 62 and the third terminal 52 being connected with the upper short contact 73 and with the lower long contact 63 which is at the same quarter point.-

ll hen the blades of this form are turned 90 clockwise from the off position shown in Figure 6, the heating elements M, N are in parallel across the wires B, G for high heat. Another quarter turn puts the element M alone in circuit giving medium heat and a third turn gives the low degree of heating by putting the elements M and N in series across the same two wires 16,0

It will be observed that to change the switch so as to adapt the circuit for a two wire supply when a three wire arrangementhas been in use, or to adapt some of a number of bases for the one arrangement and others for the other, it is necessary only to change the switch blades and the readily removable fixed contacts. The rest of the base is the same in either case and the connections from the base to the supply or lead wire terminals and to the load are unchanged except for the omission of the connection to the third wire arca es which is not used in merit,

As set forth alcove, there are three receptacle contacts opening to the bottom of the base so that an attachment plug may be used to establish the connections to the load. These receptacle contacts are the load termi nals 50, 51, 52 described alcove. They are of a well known type needing no description here and are staggered and difierently spaced so that tie plug can be connected in but one position, the correct one,

The main supply wire A is received in the groove 12, the wire B in groove 12 and C in 12 A binding post made up of a large headed screw '80 and a conductive piece rests in a recess 82 in bottom of base, a part 83 of the piece 81 heing bent in a shape rest in the groove 12, There is a similar screw 85 with a like conduc epiece forming a binding post or feed wire terminal in the groove 12 A screw 86 extends from the l dge 24 in the hay 22 through the lease and threads i o the con uctive piece for binding post 83, thus se to hold the bind ing post and the lows tact 31 in place. I like manner, a scrc holds the upper contact an Zhe loin-cling cost St) in place, being threaded from alcove to the conductive piece 81 associated e latter.

l Vhen the wire arrangement is used, there is no need ior w e in the groove 12 or for an upper contac -1- hay 22, hence the binding post cl and the screw described above may he o -itted, this arrangement, the screw 1 ds the long lower contact 61 on the ledge 24 in place of the short contact 31 used with the three wire supply. Likewise there is a binding post 8? for the groove 12 with a sccurin screw holds in place the upper contact on tne ledges 25 of the hay 23. Since corresponding contacts 43 and 72 oi the two arrangements are tooth long, this part of the device is no ditlerent for either arran ment.

The connections to the receptacle contacts are made by straps resting in deep recesses on the bottom of the base and connected by screws to the appropriate fixed contacts They remain the same for both arrangements and therefore are spoken of here as being; permanent connections between the load terminals and the quarter points. A strap 90 in the recess 91 is soldered or otherwise se cured at one end to the clips forming thereceptacle contact or load terminal 50. A screw 93 from the top of the base holds this end of the strap in the recess. At its other end, the strap 90 receives the end of a. screw 94 that extends through the shank of the upper level contact in the hay 21. Thus the strap 90 and the screw 94- iorm the connection denoted 48 in Figures 5 and 6.

Another strap 95 in a recess96 is connected to and supports the receptacle contact 52 in the two wire arrangea lilre manner and is held to the lease hy a screw 9?. A screw 98 connects it with the contacts in the hay 21 and holds these contacts in place, forming with the strap 95 the connection denoted 49 in Figures 5 and 6. ln the three wire arrangement it is the upper contact ll that is held and in the two wire arrangement, the two contacts 63 and 73 are held loy this screw 98. A short strap 99 held by a screw 100 rests in a recess 101 and sup ports the receptacle contact 51. This strap is connected with the lower level contact (either 32 or 62) on the ledge 24 of the hay 23 hy screw 102 which holds the said contact in place. This screw and strap form the connection denoted 38 in Figures 5 and 6., a""achnient plug 103 has three hlades 10 i which the lead wires from the mi point ends of the heating coils ll, N are c"- i the manner shown in Figures 5 and 6 hat when inserted into the receptacle 1 lease, the heating elements are connected with the switch co;

105 of insulating material is tom of the ease and l as holes 10 1. Electrical apparatus comprising aswitch hase three contacts for connection to A device a mounting -y switch, said mounting providt'our sw'tch points, and permanent connections h tween said contacts and ce of said points, in combination with provision ior mounting three teed wire terrainals on said base and for connecting tnree such terminals to certain of said switch points .ereloy two different sets of switch contacts a he used alternativel to we three degi es of heating either with two or with t ree of said wire terminals COIlClllCl/l7 ly connected with the switch,

2. Electrical apparatus comprising insulating loloclr, a switch well therein with provision for mounting alternative sets of lined contacts at quarter points about the well, provision for mounting three feed wire terminals on the opposite side of the base and for conductors extending therefrom to certain ot the quarter points, in combination with receptacle contacts opening to the said opposite side and permanently connected with certain o'f said quarter points, for the purpose described.

3. Electrical apparatus comprising a switch base, a well therein, a rotary switch in the well, a yoke across said well for sup porting the switch spindle and for mounting the loase, said yoke having lateral arms adapted for fastening to said base at four equally spaced points whereby said lease may he mounted in either of two positions at right angles to one another.

4-, Electrical apparatus cornprising a switch base, a Well therein, a rota-s switch in the Well, a yoke across said weil for supposeing the switch spindle and for mounting the base said yoke having fiat/em! arms adapted for iaseening to said base at four equally spaces, points whereby said base be mounted in either of two positions sighs angles to one snot-her, together Wit i'ecepzaoie contacts opening to the opposite side of said base and conneeteei to said switch in testimony Where-of 'i have sip-med my name to ibis specification.

WILLIAM EL HARRINGTQN, 

